Congressional Democrats are pursuing an extremely expensive and ill-advised expansion of a federal government program to provide health care to uninsured children. It could as much as triple the cost of this program and divert families who already have insurance into the government program. Republicans are right to fight this effort, but not by playing the immigration card.

The Senate and House next week will begin reconciling their separate bills to reauthorize SCHIP (State Children’s Health Insurance Program). SCHIP is a 10-year-old program under which the federal government offers states matching grants to fund health coverage for kids whose parents are too rich to qualify for Medicaid, but not rich enough to buy coverage on their own.

Since SCHIP, like Medicaid, is open only to U.S. citizens, parents must show birth certificates or passports to enroll their children. But House Democrats claim that such documentation requirements are too onerous. They would let states craft their own verification requirements, such as sworn affidavits from parents.

But some House Republicans are lambasting this provision as a backdoor channel for illegals seeking free health care. Reps. John Boehner of Ohio, Dennis Hastert of Illinois and Tom Tancredo of Colorado have made this the centerpiece of their attacks against the bill. “Again, the Democrats have proven their loyalty to illegal aliens over American citizens,” Tancredo rants. Rush Limbaugh has aired a whole segment on it.

The political appeal of torpedoing Democrats’ SCHIP plans by exploiting anti-immigration sentiment is obvious. But regardless of where one stands on immigration, it is hardly the issue here. By dwelling on it, Republicans only distract attention from the real problems with what Democrats are doing.

Both the Senate and House bills want to vastly expand the SCHIP program, whose current five-year tab to the federal government runs at $25 billion. The Senate bill would double this spending and the House bill triple it. Why does the Democratic-controlled Congress need so much money?

Because it wants to transform SCHIP — originally meant only as a stop-gap measure for the uninsured working poor — into an entitlement for middle- and upper-income folks. The Senate bill would not only expand benefits to include braces and therapists, it would extend eligibility to families 300 percent of the federal poverty limit — up from the current 200 percent limit.

The House bill would cover kids at 400 percent of the poverty limit — or a family of four making $83,000 annually. This constitutes about 70 percent of all American families. What’s more, the House bill redefines not just “poverty,” but also “children” to cover everyone up to age 21.

President Bush, whose fiscal conscience has been belatedly awakened, is threatening to veto this expansion of SCHIP because, even without it, spending on health care is expected to consume half of the federal budget by 2050.

In fact, Bush is trying to tighten the rules to prevent states from incrementally extending SCHIP to populations beyond those originally intended. For instance, MIChild, Michigan’s version of SCHIP, has for years covered thousands of low-income adults because it could not find enough low-income children to enroll.

Whatever the justification for doling out health care when Michgan’s coffers were flush, there is none now. Indeed, given the strain MIChild-related liabilities have put on the budget, even if Congress approves the extra money, Michigan should not take it.

That, however, is not what the Granholm administration is planning. T.J. Bucholz, a spokesman for the Michigan Department of Community Health, has already declared that it fully intends to extend the program to higher-income kids if more federal money becomes available.

That this bill would potentially bust the federal and state budgets is not its worst flaw.

According to the Congressional Budget Office, despite the relatively bare-bones benefits the SCHIP program now offers, 60 percent of its enrollees are not uninsured kids — but those whose parents dropped private coverage. This crowding-out effect would be even worse if the final bill includes the extravagant benefits Democrats are pushing.

For the first time in this country’s history, more kids might well grow up under government coverage than private coverage. This would be a giant step away from market-based reforms — and toward a national health care system similar to what Fidel Castro’s Cuba has.

This would certainly make Michael Moore happy. But it’s far from clear that Americans want a government takeover of health care. If that’s what Democrats want, Republicans should force them to openly debate their plans. That won’t happen so long as Republicans’ keep obsessing about phantom problems like illegal immigration.

Shikha Dalmia is a senior analyst at Reason Foundation, a nonprofit think tank advancing free minds and free markets. The archive of her latest work can be found here at Reason.com.